Mycoplasma genitalium is a recently identified Mycoplasma species considered to be a major cause of non-gonococcal urethritis based upon epidemiological and serological studies. In addition, M. genitalium and several other Mycoplasma species have been implicated as co-factors in AIDS. Lately, a substantial percentage of women attending STD clinics exhibit M. genitalium-associated acute and chronic infections, including cervicitis, salpingitis, adnexitis, and pelvic inflammatory disease, yet the role of M. genitalium infection in women is not fully appreciated. We propose to investigate, as part of the San Antonio STDCRC proposal, the prevalence of M. genitalium infection in Mexican- and African-American women by PCR and ELISA techniques using genital tract and blood specimens. Also, we will attempt to correlate M. genitalium with pelvic inflammatory disease, infertility, and adverse outcomes of pregnancy and minority women with or without other diagnosed STDs. In collaboration with the Behavioral and Clinical Trichomonas Projects and the Statistics/Computing Core, we intend to measure the effect of behavioral modification interventions on the incidence and adverse outcomes associated with M. genitalium infections. In addition, the establishment of M. genitalium infection is achieved primarily through adherence to and invasion of eucaryotic cells. A major focus of the proposal is to uncover the regulatory mechanism(s) of cytadherence. Our preliminary observations indicate that M. genitalium up-regulates the expression of the P140 adhesin and cytadherence-related proteins when co-incubated with eucaryotic cells and extracellular matrix components. This suggests that P140 may be regulated transcriptionally by an activator or repressor. We intend to identify the activator/repressor in order to clarify the regulatory mechanism(s) of cytadherence in this Mycoplasma species. Moreover, we recently developed a tool to knockout genes in M. genitalium, and disruption of the gene encoding the MG218 protein led to a cytadherence-negative phenotype. Further analysis revealed that the presence of MG218 is essential for the stability of the P140 adhesin. We plan to further delineate the interaction between MG218 and P140. The experimental approaches outlined represent novel strategies, and the results of the studies should enhance our understanding of cytadherence and virulence. Furthermore, these studies should identify functional targets for vaccine and diagnostic regents to control, monitor and prevent M. genitalium infection.